The top options

1. Jared Gaither, San Diego Chargers. This former Raven got a big opportunity to rebound with the Chargers. He didn’t waste it, turning in effective performances in protecting Philip Rivers’ blind side. He is the rare starting left tackle for a good passing game that might hit the market. With the future of Marcus McNeill unclear, the Chargers should make Gaither a priority re-signing.

2. Demetrius Bell, Buffalo Bills. On the positive, Bell turns 28 in May and has played on the left side. On the other hand, his career has been tainted by knee injuries. While Bills officials decide whether they want to keep him, Bell is probably seen as backup with upside on most teams.

3. Kareem McKenzie, New York Giants. Sure, he was the starting right tackle for the Super Bowl champs. But months before he turns 33 in May, McKenzie's bad knees have contributed to recent ineffectiveness. Going forward, he probably will be limited to reserve duty.

4. Jeff Backus, Detroit Lions. Backus hasn’t been dominant by any means despite being a durable starter the past 11 years. He is coming off postseason biceps surgery. Backus likely will stick with the Lions while they line up a successor.

5. Max Starks, Pittsburgh Steelers. Starks is 6-8, 340 pounds, turned 30 in January, and returned from a 2010 neck injury to fill in as a 12-game starter. The problem now is that he had knee surgery last month. His best bet to play this season is re-signing as a reserve.

6. Paul McQuistan, Seattle Seahawks. The team's left tackle torch was supposed to be passed from Walter Jones to Russell Okung, but Okung lined up for only 22 games in his first two seasons. McQuistan, at 6-6, 315 pounds, held up as a physical run blocker subbing on that side. He’ll be looked at a versatile right tackle/guard type.